The gravel chub, present only at the lower and middle Neosho stations, occupied moderate currents over clean (free of silt) gravel bottom. The gravel chub was not taken in 1957, was rare at both Neosho stations in 1958, became common at the lower Neosho station in part of 1959, but was never numerous at the middle Neosho station. Dr. F. B. Cross recorded the species as "rare" in 1952 at a collection site near my middle Neosho station, but larger numbers were taken then than in any of my collections at that station. The population was probably reduced by drought, and recovery was comparatively slow following restoration of flow. Young-of-the-year and adults were common in collections from riffles at the lower Neosho station from 1 July through 8 July, 1959. I obtained only one specimen in intensive collections in the same area on 25, 26, and 27 August. Seemingly the species had moved off shallow riffles into areas not sampled effectively by seining. #Phenacobius mirabilis# (Girard) Sucker-mouthed Minnow The sucker-mouthed minnow was common at the middle Marais des Cygnes station but was not taken at the upper and lower stations until 1959, when it was rare. At the middle and lower Neosho stations this fish increased in abundance from 1957 to 1959; at the upper station, sucker-mouthed minnows were not taken until 1959 when collections were made on the White farm. There, the species was common immediately below a low-head dam, but was not taken in extensive collections on the Bosch Farm in 1959. The species was most common immediately below riffles, or in other areas having clean gravel bottom in the current. On 5 June, 1959, many individuals were taken at night (11:30 p.m.) on a shallow gravel riffle (four inches in depth) where none had been found in a collection at 5:00 p.m. on the same date. Young-of-the-year were taken at the lower Neosho station on 24 June, 1959, and commonly thereafter in the summer. #Notropis rubellus# (Agassiz) Rosy-faced Shiner In 1958, the rosy-faced shiner was taken rarely at the lower stations on both streams. This species is common in smaller streams tributary to the lower portions of the two rivers, and probably occurs in the mainstream only as "overflow" from tributaries. Possibly, during drought, rosy-faced shiners found suitable habitat in the mainstream of Neosho and Marais des Cygnes rivers, but re-occupied tributary streams as their flow increased with favorable precipitation, leaving diminishing populations in the mainstream. #Notropis umbratilis# (Girard) Red-finned Shiner The red-finned shiner, most abundant at the upper Neosho station, occurred at all stations except the upper Marais des Cygnes. This fish seems to prefer small streams, not highly turbid, having clean, hard bottoms. It is a pool-dwelling, pelagic species. #Notropis camurus# (Jordan and Meek) Blunt-faced Shiner